1. Field of the Invention
This invention relates to a novel water soluble extract from nonpathogenic aerobic corynebacteria. More particularly, the invention relates to a water soluble extract from nonpathogenic aerobic bacteria, the said extract having the following characteristics:
(a) protein content: 3.9-5.5 mg/ml (on the basis of Bovine Serum Albumin (BSA)),
(b) sugar component: 0.41-0.52 mg/ml (on the basis of glucose),
(c) nucleic acid like substance: optical density in 260 nm/280 nm (ratio) of 1.56-162, and
(d) isoelectric point: 3.75-3.80 as well as a process of producing the extract and pharmaceutical compositions containing the extract.
2. Description of the Prior Art
It has recently been reported in various literature that cultured broth (bacterial cells) of anaerobic corynebacteria cells such as of Corynebacterium parvum and the extracts from such corynebacterial cells have ananti-cancer effect and a protective effect against infection but there had been no reports on cultured broths of aerobic corynebacteria cells. The inventors previously found that cultured broth (bacterial cells) obtained by cultivating bacterial strains belonging to nonpathogenic aerobic corynebacteria had not only an anti-cancer effect and an immunopotentiating effect for spleen cells and lymphocytes but also an anti-allergic effect which had never been attributed to a cultured broth of anaerobic corynebacteria (see, Japanese Pat. Publn. (OPI) No. 47,909/'77). However, the formerly described cultured broth (bacterial cells) were practically unsuitable for use as medicaments due to the following reasons. Since the cultured broth (bacterial cells) was insoluble in water, it must be administered in the form of a suspension. When this suspension is administered subcutaneously, it causes a marked induration at the site of injection; this is known in the case of subcutaneous injection of BCG. This adverse skin reaction makes it intolerable to continue multiple administration. As well as these practical difficulties, the cultured broth (bacterial cells) show strong toxicity.